EP1568384A1 - Process for stabilizing germinative fluid media - Google Patents

Abstract

Active substances and/or preparations are added in controlled quantities, at intervals. These agents contain one or more active components. They treat harmful organisms, using chemical and/or biological mechanisms. The organisms are killed, destroyed, damaged, inhibited, rendered harmless or otherwise combated. Simultaneously, or with a delay, air is dosed to the suspension. Air is dosed at or near the base of the tank. Preferably about 0.5 m3> of air is added per 5 m3> of the contents. Ambient air is used, blown in by compressor. The agents are biocides, such as protectives or preservatives, typically used for fluids in cooling- and process systems, and especially suspensions used in the papermaking industry. The suspension is aqueous; it is organic or inorganic. The material comprises proteins, carbohydrates and/or other hydrocarbons in organic systems, or a mixture. It is an aqueous suspension of cellulose and starch from paper manufacture. It is a cellulose suspension with solids content 0.1-80 g/l, preferably 30-60 g/l. Additions are made with pH and/or redox value control, or in terms of germ numbers present. The additives are dosed should the pH fall below 7, and/or when the redox potential falls below about -200 mV. Additions are preferably at the 25-50 ppm level. The additive is selected for the particular bacterial culture involved, and for its multiplication cycle. Vessel contents are recirculated and the agent is added at the base, with air being blown into a recirculation line. The medium is reject cellulosic material for intermediate storage in a papermaking plant. An independent claim is included for suitable equipment.

Description

TECHNICAL AREA

The present invention relates to a process for the stabilization of substantially liquid media such as e.g. Suspensions stored in a container, aerobic and / or anaerobic digestion processes. In particular, it relates to Stabilization of liquid or suspended media, which in one Paper factory can be used. In addition, she describes a metering device for Implementation of such a method.

STATE OF THE ART

For example, in the field of paper production must always container with Scrap pulp can be stabilized over a long period of time to prevent it from too strong contamination of the container contents becomes unusable. Under one Germinating in this context is a bacterial, anaerobic or aerobic Understand metabolic reaction of the container contents. These processes run without appropriate control in such media unavoidable due to nutrient-rich, mostly in addition to the ideal temperature environment from.

If the germination takes on a certain extent, then the content of such Container useless. Accompanying a strong aerobic / anaerobic microbial already in the initial stage by an undesirable odor in the container.

By "unusable" is meant that the use of the germinated Storage container contents at high follow-up costs in the process or unacceptable Process disturbances, e.g. in papermaking leads. Typically will according to preventative usually the medium with constant stirring discontinuously fed a biocide, which is the aerobic / anaerobic microbial should prevent.

Such methods can also be applied preventively to a "Tipping" of the container contents in an unusable state from the outset excluded.

As the biocides are ecologically not unproblematic substances (See, for example, the European Directive 98/8 / EC), is a housekeeping Handling of such chemicals nowadays prescribed, and stabilization For example, it is not easy to over-supplement biocides realizable.

PRESENTATION OF THE INVENTION

The invention is therefore based on the object, an improved respectively alternative process for the stabilization and / or sterilization of substantially liquid, stored in at least one container, aerobic and / or anaerobic Degradation processes subjected media such. To propose suspensions.

Essentially, it is about extending the storage time, and / or the Reduce biocide levels, and thus an ecologically improved process to reach.

The solution of this problem is achieved in that at least temporarily the Medium active substances and / or preparations containing one or more active substances intended to be too rapid, in particular chemically To prevent growth of harmful organisms to be fed, and that at the same time the medium is metered in air.

The essence of the invention is thus to recognize that a combination of the Addition of biocide and air prolonged shelf life of such media allowed.

Typically, for example, in the field of storage of pulps from the Paper production storage times are achieved, which are three times as large as Storage times with conventional treatment. So while typically such containers in prior art methods after 2-3 days of storage unusable, you can use the proposed method over be held for a week.

The combined addition of both air and biocide is preferably carried out in Intervals (in batches), usually together with a revolution of the Container contents.

According to a first preferred embodiment of the method, the air is in Bottom area and / or dosed in the ground-level area of the container. Especially in such a supply, the anaerobic processes in the container through the Air addition can be optimally influenced. The addition of air can thereby by specific arranged in the ground area lines done in a distributed manner.

In a concrete application, 200 Nm ³ / h of air are added in a 2000 m ³ tower at an interval over a period of 2 hours combined with a special biocide. It thus proves to be advantageous to meter in per 5 m ^{3 of} medium in the range of 0.3-1.5 m ³ , preferably in the range of 0.5m ^{3 of} air. This usually at a solids content in the medium of about 30-60 g / l.

It turns out that in most cases it is sufficient to introduce ambient air, which is preferably injected via a compressor.

The biocides useful for such use in combination with air can from the company Biomontan (AT) under the trade name "Petrosid". In other words, it is preferably a biocide and / or a biocide Preparation (at least partially containing biocidal agents), which chemically and / or biologically the anaerobic and / or in particular the aerobic contamination of preferably biological aqueous organic systems prevents or reverses. Further preferably, such contains Composition also stabilizers.

The liquid medium to be stabilized is, for example an aqueous solution, suspension and / or an aqueous slurry of organic biological material, preferably organic biological material around proteins, hydrocarbons, starch, cellulose, glycogen or a mixture thereof. But also all other liquid media, which Biodegradation processes are subject to this process be stabilized. In particular e.g. is the liquid medium in the essentially an aqueous slurry of cellulose and starch, in particular a papermaking pulp slurry.

The addition of air and biocide is carried out as a function of a pH and / or redox value measured in the medium and / or as a function of the bacterial count in the medium. This allows the process to be optimally controlled and, in particular, the addition of biocide be kept to a minimum. In particular, it has proven in the field of paper processing to be advantageous to the active ingredient and / or preparation in an amount ranging from 10 to 50 ppm, preferably about 25 ppm (by volume of biocide based on the contents of the container absolutely dry, ie absolutely dry) to meter.

Typically, to increase the storage times of the drug and / or the preparation depending on the bacterial culture present in the medium be selected, respectively, successively the time course of this bacterial culture be adjusted.

The method can be used advantageously in particular when the container has at least one recirculation line for circulating the medium, with which medium is introduced in the floor area and / or in the floor area, the air then being e.g. injected into at least one of these recirculation lines becomes. Alternatively, air can also be delivered via nozzles or via air lances into the container be introduced. About the same recirculation line can also biocide be supplied. The biocide can also be supplied via other channels. It should be distributed as homogeneously as possible in the container. Because the container typically has a stirrer, distribution among others This agitator can be guaranteed.

As already mentioned above, the proposed method can be particularly efficient for the storage of liquid resp. suspended media are used, which should be stored in a paper mill.

Further preferred embodiments of the inventive method are in described the dependent claims.

Furthermore, the present invention relates to an apparatus for performing a Procedure as described above. The method is in particular characterized in that at least one container is provided, which via the first means with which active substances and / or preparations (for example biocide) be supplied controlled and distributed, and which has second means, with which at the same time the medium air in the ground area and / or near the ground Area of the container is metered. Particularly preferably, the container has additionally via third agents, with which pH and / or redox value and / or the Germ count in the medium to be measured, with the dosage of active ingredient and / or preparation and / or air depending on at least one of these measured values happens. For example, is in the application of the method in the Paper processing with the addition of air respectively biocide then used when the pH value in the acidic region tilts (pH drops below 7) and / or if a redox potential is measured, which is below about -200 mV.

Furthermore, the present invention relates to an active ingredient and / or preparation which contain one or more active substances intended to be used on chemical and / or biological ways of destroying, deterring, harmful organisms to harm them or to prevent them from harming them A method for use in a method as described above.

Further preferred embodiments are in the dependent claims described.

WAYS FOR CARRYING OUT THE INVENTION

The proposed air biocide process serves to create liquid media in Storage containers, which have become unusable due to aerobic / anaerobic microbial contamination are to be saved or returned to a usable state, respectively such to store liquid media in storage containers from corresponding contamination (Prevention).

Specifically, in the present case as an embodiment, a container with However, it must be emphasized be that the present process in principle to all liquid media, d. H. aqueous solutions or suspensions of substances respectively Solid body components which are due to aerobic / anaerobic microbial contamination can become unusable. For example: Storage tanks for return water, dekstoff, pulp, fruit juices, oils, slurries.

The term "unusable" in this context means that the use of the contaminated storage container contents to high follow-up costs in the process or unacceptable Process disturbances leads. For example, when the liquid medium is around Rejected pulp from the papermaking trade, since in the subsequent Production process of paper the presence of microbial contamination too Process difficulties and similar cause can give.

Accompanying the aerobic / anaerobic contamination is already in the initial stage usually due to an undesirable odor in the container. By Application of the method can prevent this odor, the pH raised and the redox value direction shifted positive.

The method can also be used preventively to prevent "tilting" of the To exclude container contents in a useless condition from the outset. In addition, biocide treatment costs can be lowered, the effect of Biocides can be increased or process chemicals can be saved.

General description of the method:

The air biocide process is particularly applicable when aerobic in the tank as well also anaerobic conditions or the container threatens, from the aerobic area in to "tip" the anaerobic area.

In most cases, the contamination of the container contents begins under aerobic conditions. These outweigh as long as enough oxygen is available.

The change to the anaerobic area can be made by an online pH and / or Redox measurement at the substance discharge or by a corresponding laboratory measurement (if necessary also online) of the microbial contamination. If the container tips, e.g. in the Paper processing in the acidic pH range and / or becomes a redox potential measured below about -100 mV, it can be assumed that the Change to the anaerobic area has taken place.

If such limit values are undershot for redox and pH or if a certain number of anaerobic germs in the container are exceeded, air is metered in the bottom region of the container. The air is supplied by external air is injected via a compressor in the bottom area. Typically, for example, in the area of paper processing, it is sufficient to blow in approx. 0.5m ^{3 of} air per 5 m ^{3 of} container contents.

According to the invention, biocide is preferably added to the air simultaneously with the air Container contents dosed. The biocide becomes the bacterial culture of the container contents customized. It may also contain preservatives.

If there is insufficient mixing in the container through a stirrer is guaranteed to stir the biocide, this can be done via a Recirculation line, which is intended to circulate the container contents, be dosed.

The measurements of pH or redox or germ count are advantageous when a preventive treatment of the contents of the container should take place. They are also beneficial to the effectiveness of the treatment of an unusable container contents with the in a controlled manner, and to ensure that that biocide is used in an ecologically optimal way.

As a result, it appears that in the field of such containers with reject pulp in the paper industry storage times of more than 7 days even up to 10 days are possible while normally such containers under the exclusive use of Biocide can be stored only 2-3 days, then the germination is like this advanced that the contents of the container can no longer be brought into the process.

The supply of air as well as the supply of biocide may be at intervals of e.g. 2h are made, in which both components are supplied.

Example:

A coated scrap storage tower on a paper machine for producing wood-free coated paper (broke tower) having a content of 2000 m ³ is to be stabilized in terms of germination / pH / redox value.

The aim is to stabilize the microbial contamination, and according to the pH and of the redox value in this tower. The solids content in the tower is 30-60 g / l, i. 3-6% by weight.

PH and redox are measured in a recirculation line using Standard electrode methods. Under "good" conditions, a pH value in Range of 8 measured, and a redox potential of about +100 mV. The Recirculation line is operated with a separate pump, the Container contents within 2 - 8h is completely circulated. The fabric is on Drained container bottom and introduced again in the upper container part.

The content has a very high dissolved starch content (about 0.1 wt .-%), d. H. For Bacteria, food is always present in excess. This starch is the ideal nutrient for bacteria. Therefore, the container contents germinate within a few hours, with especially the facultative anaerobic bacteria are disturbing. This is measurable by a drop in the pH from 8 to about 6 and the redox value of +100 mV to about -300 mV, because the bacteria excrete acids during metabolism.

In the beginning there is predominantly a growth of bacteria under aerobic conditions instead of. When the oxygen in the water is consumed, optionally change aerobic Bacteria in the anaerobic area. This type of bacteria is in this container in to find a large number. The change into the anaerobic area can be done by a Drops of redox potential and pH are measured tower by comparison above). Threshold values are usually assumed to be 7 for the pH be, and for the redox potential of -200mV.

In the recirculation line of the container is regularly (i.e., for example, once a day) but discontinuously biocide (i.e., e.g., every 2-4 hours) was added to conserve the substance and the bacterial population under a certain Maximum value.

But if the residence time of the substance by too small a decrease of the following Paper machine gets too high, so does the level of microbial contamination and "tilting" in the anaerobic area is observed. The pH and redox measurements in the Recirculation line indicate this point (falling below the above Thresholds).

If the growth of anaerobic bacteria and facultative anaerobic bacteria begins, air is metered into the container. The air dosing is done either via the Recirculation line or via some dosing nozzles in the conical bottom area.

The air dosing is 100 Nm ³ / h (Nm ³ = standard cubic meter) over a period of about 4 hours (the period depends inter alia on the intensity of the microbial contamination and on the type of medium). A next cycle of this kind will only be triggered again when the thresholds are exceeded again. The dosing of air within an interval is adjusted to the evolution of the pH and redox value, ie it is dosed until a satisfactory development in pH and redox can be observed (ie the thresholds are exceeded again).

Biocide is mixed with the air at the same time. This in an amount of about 25ppm (Vol. Biocide / kg atro content). The question comes, for example, the biocide Petrosid D20, how it is available from the company Biomontan (AT).

In addition, the biocide quantity and type are adjusted during the dosing of air. It is first with a combination of air and / or killer biocide the Bacteria population is reduced, then with a combination of air and / or Preservative stable conditions for the next 8-24 hours created.

If the method is practiced preventively, then the limits in the Residence time, with the pH and redox value placed relatively close to the ideal state. Will that be Procedures practiced preventively, it is regularly, d. H. for example, once per Day or every two days, during a given interval of, for example, 4 Hours blown air and fed biocide. The length of the intervals whose Time interval and the amount of air supplied or the supplied Biocides is adjusted so that the measured values never go too far below the Move thresholds. In this way, much less biocide than at Procedures introduced in the prior art, and it can nevertheless preventive stable conditions are guaranteed in the dream.

Claims (16)

Process for the stabilization and / or sterilization of essentially liquid media stored in at least one container and subject to aerobic and / or anaerobic degradation processes, in particular suspensions,
characterized in that
at least temporarily the medium active ingredients and / or preparations containing one or more active substances which are intended to destroy, deter, render harmless, prevent damage by them or in other ways to chemically and / or biologically harmful organisms fight, be fed controlled,
and that air is metered into the medium at the same time or with a time lag. A method according to claim 1, characterized in that the air is metered in the bottom region and / or in the near-bottom region of the container. Method according to one of the preceding claims, characterized in that per 5 m ^{3 of} medium in the range of 0.3-1.5 m ³ (standard cubic meter), preferably in the range of 0.5m ³ air is metered. A method according to claim 3, characterized in that it is the ambient air in the air, which is preferably injected via a compressor. Method according to one of the preceding claims, characterized in that the active substances and / or preparations are biocides such as protective and / or preservative for liquids in cooling and process systems, in particular from the field of the paper industry. A method according to claim 5, characterized in that it is a biocide and / or a biocidal preparation which prevents or reverses the anaerobic and / or aerobic bacterial contamination of aqueous, in particular suspended media systems by chemical and / or biological means. Method according to one of the preceding claims, characterized in that it is the liquid medium to an aqueous solution, respectively. a suspension of inorganic and / or organic substances, wherein it is preferably in the substances to proteins, carbohydrates and / or other hydrocarbons, respectively. organic systems or a mixture thereof. A method according to claim 7, characterized in that the liquid medium is essentially an aqueous slurry of cellulose and papermaking starch. A method according to claim 8, characterized in that it is the liquid medium is a pulp slurry from papermaking with a solids content in the range of 0.1-80 g / l, preferably from 30 to 60 g / l. Method according to one of the preceding claims, characterized in that the combined addition of biocide active substance or of air is carried out as a function of a pH and / or redox value measured in the medium and / or as a function of the number of bacteria in the medium. A method according to claim 10, characterized in that the combined addition of biocidal active ingredient is triggered when the measured pH tilts in a range below pH 7 and / or when the redox potential falls below about -200 mV. Method according to one of the preceding claims, characterized in that the active ingredient and / or the preparation in an amount of 10 to 100 ppm, preferably about 25 to 50 ppm are added. Method according to one of the preceding claims, characterized in that the active ingredient and / or the preparation is selected depending on the bacterial culture present in the medium, or is adapted to the time course of this bacterial culture. Method according to one of the preceding claims, characterized in that the container has at least one recirculation line for circulating the medium, with which medium in the bottom area and / or near the ground is introduced, and that the air is preferably injected into at least one of these recirculation lines. Method according to one of the preceding claims, characterized in that the medium is reject pulp which is to be temporarily stored in a paper mill. Device for carrying out a method according to one of the preceding claims, characterized in that at least one container is provided which has first means with which active ingredients and / or preparations are supplied in a controlled and distributed manner, which has second means with which simultaneously Medium air is added in the bottom region and / or in the near-bottom region of the container, and which has third means with which pH and / or redox value and / or the germ count value in the medium are measured, wherein the dosage of active ingredient and / or Preparation and / or air in dependence of at least one of these measured values happens.